00284nam a2200097Ia 4500008004100000082003000041100002100071245005600092260003000148300000800178140113s9999    xx            000 0 und d  a631.442.42:633.002.2   L3  a"Allieson, F.E."  aSoil organic matter and its role in crop production  a1973bElseviercAmsterdam  a637